Self-propelled skateboard



FIG. 1 is a perspective view of a self-propelled skateboard, showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a left-side elevation view thereof;

FIG. 5 is a right-side elevation view thereof;

FIG. 6 is an enlarged front elevation view thereof; and,

FIG. 7 is an enlarged rear elevation view thereof.

The broken lines are for the purpose of illustrating portions of the article that form no part of the claimed design. 

CLAIM The ornamental design for a self-propelled skateboard, as shown and described. 